Standardized Field Sobriety Tests

The National Highway Traffic Safety Administration has adopted standardized field sobriety tests (“SFTS”) that may produce reliable indications of intoxication. But they are only reliable if police administer the tests correctly.

The three SFTS tests and the “clues” that law enforcement officers look for are based on the premise that intoxicated drivers cannot effectively divide their attention between two tasks. For example, an intoxicated driver cannot maintain balance while focusing on the officer’s instructions or counting steps while walking in a straight line. In order for the tests to be reliable, the officers must provide adequate instructions and properly demonstrate the tests. The officer must also properly score the clues. If you have taken SFTS’s, you may ask yourself, “Did I pass the tests?” But you should also ask, “Did the officer properly instruct and score my performance on the tests?”

The horizontal gaze nystagmus test requires an officer to use a defined point, usually a pen or a light, that the driver can follow with his eyes. Officers watch for the driver to turn his head as he is watching the pen rather than remain still and follow the pen only with his eyes. The officer will watch to check whether the driver’s pupils are equal and able to focus. The officer will then pass from his left to his right and back to center, then from center to left and back again. The officer is testing whether the driver’s eyes can pass in “smooth pursuit” of the pen.

The walk-and-turn test is the first of two tests that require the driver to stand in an awkward position, without swaying or losing balance, and listen as the officer describes the test and shows a demonstration of how the test should be performed. During this time the officer is attempting to divide the driver’s attention between listening to the instructions and maintaining balance. Once the officer describes the test and briefly demonstrates the test, the officer will tell the driver to begin. The driver must perform the test as instructed and without losing balance or stepping off the line. Furthermore, he must take only nine steps and turn correctly with short, choppy steps, pivoting on his left foot. If he does any of these tasks improperly, the officer will score the imperfection as a clue of impairment.

The third SFST is the one-leg stand. This test requires the driver to stand at attention, without losing balance, while listening to the officer’s instructions. The officer will then ask the driver to raise one foot approximately six inches off of the ground and point his toe outward. The officer will ask the driver to look at his foot and keep his arms approximately six inches away from his side. Like the walk and turn, the officer is waiting for him to use his arms for balance.

A driver’s inability to perform divided attention tasks is evidence of intoxication. On the other hand, successful completion of the tests can be a defense to DUI charges.

SFST’s are usually recorded on video and audio. You should not rely on an officer’s conclusion that you failed the tests. It is important to hire a DUI attorney who evaluate the video and audio independently of the officer’s conclusions. Our DUI lawyers are well versed in the SFST’s. We know how to examine a driver’s performance. We can determine if the officer properly instructed, demonstrated, and scored performance on the tests. Contact our DUI attorneys to arrange a case evaluation.